This invention relates generally to the art of electrostatic printers, and more particularly to those such printers in which an electrostatic field is used to create an ink jet from a print head to a recording carrier.
The concept of generating ink jets using a strong electrostatic field is well known in the art. However, in most jet-type electrostatic printers, there are nozzles located at print heads which dispense the ink for forming jets. Examples of such devices are found in U.S. Pat. Nos. 3,060,429 to Winston, 3,585,060 to Gourdine et al., 3,579,245 to Berry, 3,916,421 to Hertz, and 3,914,772 to Kashio. A problem with these devices is that the nozzles thereof tend to clog with contaminants. A related problem is that the ink must be maintained as contamination free as possible to avoid clogging; thus, increasing the cost of operation. Therefore, it is an object of this invention to provide a ink-jet printer in which the jet-forming elements are immuned to clogging.
It is a further object of this invention to provide such a printer which is uncomplicated and relatively inexpensive to manufacture and operate.
There are a number of U.S. Patents disclosing devices which include matrices of selectively-energized printing elements for printing overlapping dots to form lines. Such patents include U.S. Pat. Nos. 3,052,213 to Schaffert, 3,750,564 to Bettin, 3,834,301 to Croquelois et al., 3,900,094 to Larsen et al., and 3,913,719 to Frey. In addition, the jet printer disclosed in the Hertz patent mentioned above (U.S. Pat. No. 3,916,421) also discloses a matrix used for printing. The devices mentioned in these patents are related to the present invention in that many of the control circuits therein could be used in the present invention, and, in particular, the control circuit of Frey (3,913,719) is hereby incorporated into this patent by reference.